Agrammatic and non-brain-damaged subjects' verb and verb argument structure production

This study examined verb and verb argument structure production in 10 agrammatic aphasic and 10 non-brain-damaged subjects. Production of six types of verbs was examined in two conditions-a confrontation and an elicited condition; and production of verb arguments was examined in a sentence condition in which each target verb was elicited with all possible argument structure arrangements. Results showed statistically significant differences between the aphasic and non-brain-damaged subjects in all conditions, but no significant differences were found between confrontation and elicited labelling conditions for either subject group. The aphasic subjects, however, produced obligatory one-place verbs correctly significantly more often than three-place or complement verbs in the elicited condition and a consistent hierarchy of verb difficulty was found in both the confrontation and elicited conditions, For both subject groups sentence production was influenced by the number of arguments or participant roles and by the type of arguments required by the verb. In addition, the complexity of the verb (i.e. the number of possible argument structure arrangements) influenced sentence production with simple verbs produced correctly with their arguments more often than complex ones. Finally, obligatory arguments were produced correctly more often than optional ones, even when production of the optional arguments was requested. These data indicate that the argument structure properties of verbs are important dimensions of lexical organization that influence both verb retrieval and sentence production in agrammatic aphasic subjects.